This invention relates to an apparatus for cleaning movable parts of a displacement-type liquid level sensor. Liquid level sensors are used in the chemical process industry to indicate and control the amount of process liquid in a vessel. The displacement type of sensor measures the buoyant force exerted by the liquid on a displacer which is partially or completely submerged in said liquid. An example of such a sensor is the "Level-Trol" model manufactured by Fisher Controls Company.
Some liquids used in chemical processes tend to form solid particles while they are stored in a vessel. This may occur by a number of mechanisms, some of which are:
(1) accumulation of particulate impurities from the liquid, (2) evaporation and drying of the liquid leaving salt precipitates, (3) freezing of the liquid, and (4) polymerization of liquid or the impurities contained therein.
The solid materials formed tend to collect on various parts of the liquid level sensor exposed to the environment inside the vessel. When this happens, the movable parts of the sensor jam and cause false indications of liquid level in the vessel. To correct this in the past it has been necessary to disconnect and remove the sensor from its service location so that it could be dismantled and cleaned manually.